Rozhen Observation Calendar

Which nights are best for a target over the coming weeks. The astronomy mark (darkness × altitude × Moon) is computed for every night; the weather and the overall mark exist only where Open-Meteo has a forecast (the next four days) or ERA5 history (past nights) — the rest is honestly blank.

Best nights for North America Nebula: 10-20 (100), 10-21 (100), 10-22 (100), 11-03 (100), 11-04 (100) — by astronomy; check the weather when the night is within four days.

2039-10-20astronomy score per night — click a bar for that night2039-11-18

night of	astronomy	weather	overall	best window	highest	dark h	Moon	Moon sep.
2039-10-20 Thu	100	—	unknown	20:10–02:45 (good, 6.58 h)	87.2° 20:25	10.03	13%	89.5°
2039-10-21 Fri	100	—	unknown	20:05–02:40 (good, 6.58 h)	87.2° 20:20	10.07	22%	82.8°
2039-10-22 Sat	100	—	unknown	20:05–02:35 (good, 6.5 h)	87.2° 20:15	10.11	32%	76.7°
2039-10-23 Sun	99	—	unknown	20:05–02:35 (good, 6.5 h)	87.2° 20:15	10.15	44%	71.3°
2039-10-24 Mon	91	—	unknown	20:00–02:30 (good, 6.5 h)	87.2° 20:10	10.19	55%	67.0°
2039-10-25 Tue	82	—	unknown	20:00–02:25 (good, 6.42 h)	87.2° 20:05	10.23	66%	64.1°
2039-10-26 Wed	68	—	unknown	20:00–01:50 (good, 5.83 h)	87.2° 20:00	10.27	75%	62.8°
2039-10-27 Thu	65	—	unknown	20:00–23:20 (good, 3.33 h)	87.2° 20:00	10.31	84%	63.0°
2039-10-28 Fri	62	—	unknown	19:55–21:10 (good, 1.25 h)	87.2° 19:55	10.35	91%	64.7°
2039-10-29 Sat	60	—	unknown	19:55–21:05 (good, 1.17 h)	87.2° 19:50	10.38	96%	67.7°
2039-10-30 Sun	62	—	unknown	18:55–20:35 (good, 1.67 h)	87.2° 18:45	10.42	99%	71.7°
2039-10-31 Mon	67	—	unknown	18:55–21:35 (good, 2.67 h)	87.2° 18:40	10.46	100%	76.4°
2039-11-01 Tue	75	—	unknown	18:50–22:10 (good, 3.33 h)	87.2° 18:40	10.5	99%	81.6°
2039-11-02 Wed	79	—	unknown	18:50–22:50 (good, 4.0 h)	87.2° 18:35	10.53	96%	87.0°
2039-11-03 Thu	100	—	unknown	18:50–23:35 (good, 4.75 h)	87.2° 18:30	10.57	92%	92.5°
2039-11-04 Fri	100	—	unknown	18:50–00:15 (good, 5.42 h)	87.2° 18:25	10.6	86%	97.8°
2039-11-05 Sat	100	—	unknown	18:50–00:20 (good, 5.5 h)	87.2° 18:20	10.64	79%	102.9°
2039-11-06 Sun	100	—	unknown	18:45–00:25 (good, 5.67 h)	87.2° 18:20	10.67	71%	107.5°
2039-11-07 Mon	100	—	unknown	18:45–00:25 (good, 5.67 h)	87.2° 18:15	10.71	62%	111.4°
2039-11-08 Tue	100	—	unknown	18:45–00:25 (good, 5.67 h)	87.2° 18:10	10.74	52%	114.5°
2039-11-09 Wed	100	—	unknown	18:45–00:20 (good, 5.58 h)	87.2° 18:05	10.77	42%	116.5°
2039-11-10 Thu	100	—	unknown	18:45–00:25 (good, 5.67 h)	87.2° 18:05	10.8	33%	117.3°
2039-11-11 Fri	100	—	unknown	18:45–00:20 (good, 5.58 h)	87.2° 18:00	10.83	23%	116.5°
2039-11-12 Sat	100	—	unknown	18:40–00:15 (good, 5.58 h)	87.2° 17:55	10.87	15%	114.1°
2039-11-13 Sun	100	—	unknown	18:40–00:10 (good, 5.5 h)	87.2° 17:50	10.9	8%	110.3°
2039-11-14 Mon	100	—	unknown	18:40–00:05 (good, 5.42 h)	87.2° 17:45	10.93	3%	105.1°
2039-11-15 Tue	100	—	unknown	18:40–00:05 (good, 5.42 h)	87.2° 17:45	10.95	0%	99.0°
2039-11-16 Wed	100	—	unknown	18:40–00:00 (good, 5.33 h)	87.2° 17:40	10.98	1%	92.2°
2039-11-17 Thu	100	—	unknown	18:40–23:55 (good, 5.25 h)	87.2° 17:35	11.01	4%	85.4°
2039-11-18 Fri	100	—	unknown	18:40–23:50 (good, 5.17 h)	87.2° 17:30	11.04	10%	78.8°

Download: CSV · JSON

💡 API

curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&date=2039-10-20&days=30"
curl -sS "https://devops.majbase.com/rozhen-planner/calendar-api?target=M31&days=30&format=csv" -o m31-calendar.csv

One row per night: score_astronomy always, score_weather / score only where a forecast or history exists (null otherwise, with weather_source saying which), best window, dark hours, Moon illumination and separation, transit. 7–60 nights. Errors: 400 with invalid_date or target_unresolved. Results are cached for six hours; calculation version 2026-10-10.1.